978 AN INTRODUCTION TO ENTOMOLOGY 



from the Evanioidea in that the petiole of the abdomen is attached 

 to the hind end of the propodeum ; and it differs from the Vespoidea 

 in that there is on each side a lateral extension of the pronotum in 

 the form of a distinctly differentiated rounded lobe, which covers 

 the spiracle (Fig. 1195, B); these lobes are known as the posterior 

 lobes of the pronotum ; they do not reach the tegulae except in some 

 Drsnnidae and Ampulicidas. These exceptional forms can be placed 

 in their families by the table on pages 906 to 914. 



The families constituting the superfamily Sphecoidea, which can 

 be separated by the table referred to above, represent two quite dis- 

 tinct groups of families, known respectively as the sphecoid-wasps 

 and the bees. These two groups of families are distinguished as 

 follows. 



A. First segment of the posterior tarsi cylindrical and naked; or with but little 



hair; hairs clothing the thorax simple; nests provisioned with animal food. 



p. 978 The Sphecoid- Wasps 



AA. First segment of the posterior tarsi elongate and dilated; some of the hairs, 



especially of the thorax, plumose; nests provisioned with honey and pollen. 



p.989 The Bees 



THE SPHECOID-WASPS 



The group known as the Sphecoid-wasps includes three families, 

 the Ampulicid£e,the Dryinidse, and the Sphecidaj. These three fam- 

 ilies and certain families of the Vespoidea were formerly classed to- 

 gether as the Fossores or digger-wasps ; which names were suggested 

 by the fact that most of the species belonging to these families make 

 nests for their young by digging burrows in the ground or in wood. 

 But this group is no longer regarded as a natural one notwithstanding 

 the striking similarity in habits exhibited by its members. 



The family AMPULICID^ is represented in our fauna by only 

 two genera, Rhindpsis and Dolichtirus, the species of which are very 

 rare. So far as is known the members of this family prey on cock- 

 roaches, with which they store their nests. 



Family DRYINID^ 

 The Dryinids 



This family is composed of small parasitic wasps; it is widely 

 distributed over the world and is represented in our fauna by many 

 genera. 



The fore wings have a lanceolate or ovate stigma ; the hind wings 

 are without closed cells; the antennas consist of ten segments, the 

 anterior tarsi of the female are usually chelate; and either the pro- 

 notimi has a longitudinal sulcus or the antennas are borne close to 

 the clypeus. The females of the genus Gondtopus are wingless, ant- 

 like, and are without a scutellum. 



These parasites confine their attacks to the homopterous insects 

 belonging principally to the families Fulgoridse, Membracids, and 

 Cicadellidas. 



